title: Physiological differences between black and white runners during a treadmill marathon.
abstract: To determine why black distance runners currently out-perform white distance runners in South Africa, we measured maximum oxygen consumption (VO2max), maximum workload during a VO2max test (Lmax), ventilation threshold (VThr), running economy, inspiratory ventilation (VI), tidal volume (VT), breathing frequency (f) and respiratory exchange ratio (RER) in sub-elite black and white runners matched for best standard 42.2 km marathon times. During maximal treadmill testing, the black runners achieved a significantly lower (P less than 0.05) Lmax (17 km h-1, 2% grade, vs 17 km h-1, 4% grade) and VI max (6.21 vs 6.82 l kg-2/3 min-1), which was the result of a lower VT (101 vs 119 ml kg-2/3 breath-1) as fmax was the same in both groups. The lower VT in the black runners was probably due to their smaller body size. The VThr occurred at a higher percentage VO2max in black than in white runners (82.7%, SD 7.7% vs 75.6%, SD 6.2% respectively) but there were no differences in the VO2max. However, during a 42.2-km marathon run on a treadmill, the black athletes ran at the higher percentage VO2max (76%, SD 7.9% vs 68%, SD 5.3%), RER (0.96, SD 0.07 vs 0.91, SD 0.04) and f (56 breaths min-1, SD 11 vs 47 breaths min-1, SD 10), and at lower VT (78 ml kg-2/3 breath-1, SD 15 vs 85 ml kg-2/3 breath-1, SD 19). The combination of higher f and lower VT resulted in an identical VI.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Physiology, University of Cape Town Medical School, South Africa.
authors.forename: A N
authors.initials: AN
authors.lastname: Bosch
authors.forename: B R
authors.initials: BR
authors.lastname: Goslin
authors.forename: T D
authors.initials: TD
authors.lastname: Noakes
authors.forename: S C
authors.initials: SC
authors.lastname: Dennis
mesh_terms: D000328:Adult; D044383:Black People; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D012119:Respiration / Q000502:physiology; D012420:Running; D012885:Skinfold Thickness; D044465:White People
chemical_list: D001786:Blood Glucose; D007773:Lactates; D019344:Lactic Acid